A Red Arrows jet has crashed after an incident at RAF Valley in north Wales, the Ministry of Defence said.
It is understood two people were on board the Hawk aircraft which crashed at the Anglesey base used to train the UK's fighter pilots on Tuesday afternoon.
Here is a list of other air disasters involving fighter planes in Britain in recent years.
- August 2015 - Eleven men were killed when a vintage Hawker Hunter jet plummeted on to the A27 in West Sussex during a loop-the-loop stunt at the Shoreham Airshow. A further 13 people, including the pilot Andy Hill, were injured.
The disaster led to the cancellation of the Red Arrows performing stunts at the Farnborough Air Show for the first time in more than 50 years over safety fears.
- August 2015 - RAF-trained fast jet pilot Kevin Whyman, 35, was killed when his Folland Gnat aircraft plummeted during an aerial display at the CarFest event in Oulton Park, Cheshire.
- November 2011 - Highly experienced Red Arrows pilot Sean Cunningham, 35, was fatally injured when he was ejected from the cockpit of a Hawk T1 aircraft while on the ground at RAF Scampton, Lincolnshire. A coroner ruled that the safety pin on the ejector seat had been "entirely useless".
- August 2011 - Red Arrows Flight Lieutenant Jon Egging, 33, was flying a Hawk T1 when it came down into a field after he pulled six times the force of gravity at an air show near Bournemouth Airport, killing him instantly.
- September 2007 - James Bond stuntman Brian Brown, 49, died when he crashed a Second World War Hurricane after carrying out an unplanned barrel roll at a re-enactment of the Battle of Britain at Shoreham Air Show, West Sussex.
The Red Arrows are a world-famous aerobatic team, performing stunts and daredevil displays in the distinctive Hawk fast-jets.
Based at RAF Scampton in Lincolnshire, their usual display covers an area over six miles, with jets flying as close as 15ft apart at more than 400 miles an hour, sometimes flying just 100ft above the ground.
Some 1,500 service personnel, civil servants and contractors work at RAF Valley on Anglesey, which is also home to the military's search-and-rescue, post-crash team.